The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Electrically-powered devices require a power source. Electrical power can be supplied in a variety of ways, including through wiring from a centralized source or from a battery. Many electrical devices are used on mobile platforms, such as aircraft, aerospace vehicles, rotorcraft, etc. The wiring typically used in these applications is heavy and costly. The use of batteries requires periodic replacement and/or recharging. In addition, a battery contains corrosive materials, and this can be a factor in limiting the use of a battery in some applications. Furthermore, in some aerospace and aircraft applications such as flight testing, various forms of sensors are located in areas where it would be costly to route power wiring.
Various attempts have been made to use piezoelectric material as a component of an energy harvesting device. When piezoelectric material is strained, an electrical charge is generated through the coupling of the mechanical and electrical states of the material. The charge generated can be useful electrical energy. The development of areas and methods of harnessing this electrical energy is finding considerable interest at the present time for their potential to power various forms of sensors and electrical components, and especially in applications where it is impractical or difficult to make use of a battery and/or wiring leading to the sensor or device.
Various forms of piezoelectric devices have attempted to convert vibrating energy from a structure into useful electrical energy. However, many piezoelectric energy harvesting devices have difficulty harvesting vibration energy at low frequencies (i.e., frequencies typically less than 100 Hz). The problem with such piezoelectric devices is their lack of sensitivity to low frequency vibration energy. A device able to convert low frequency vibration energy into useful electrical energy would thus prove highly useful in a wide variety of applications where the need exists to power a remotely located sensor or other form of electronic device.